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    <title>Document</title>
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<script>

    function join(){
        var str = "";
        for (var i =0; i< arguments.length;i++){
            if(i==0){
                str = arguments[i];
            }else{
                str += "|" +arguments[i];
            }
        }
        return str;
    }

    console.log(join("hello","world"));
    //ES6方式
    function join2(...strs){
        var str = "";
        for (var i =0;i<strs.length;i++){
            if(i == 0){
                str = strs[i];
            }else{
                str +="|" + strs[i];
            }
        }
        return str;
    }

</script>
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